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fix(webview): throttle state pushes to prevent gray screen OOM #1077

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0b02f7d
fix(webview): throttle large state updates
JunyongParkDev Jul 30, 2026
fb369bb
test(task): guard immediate clean state on start
JunyongParkDev Jul 31, 2026
9d9bfa3
fix(webview): flush unanswered asks before message events
JunyongParkDev Jul 31, 2026
11be8e5
test(webview): cover non-Error state post failures
JunyongParkDev Jul 31, 2026
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19 changes: 11 additions & 8 deletions src/core/task/Task.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -551,12 +551,9 @@ export class Task extends EventEmitter<TaskEvents> implements TaskLike {
this.emit(RooCodeEventName.QueuedMessagesUpdated, this.taskId, this.messageQueueService.messages)
void this.providerRef
.deref()
?.postStateToWebviewWithoutTaskHistory()
?.postStateToWebviewThrottled()
.catch((error) => {
console.error(
"[Task#messageQueueStateChangedHandler] postStateToWebviewWithoutTaskHistory failed:",
error,
)
console.error("[Task#messageQueueStateChangedHandler] postStateToWebviewThrottled failed:", error)
})
}

Expand Down Expand Up @@ -1047,9 +1044,13 @@ export class Task extends EventEmitter<TaskEvents> implements TaskLike {
private async addToClineMessages(message: ClineMessage) {
this.clineMessages.push(message)
const provider = this.providerRef.deref()
// Avoid resending large, mostly-static fields (notably taskHistory) on every chat message update.
// taskHistory is maintained in-memory in the webview and updated via taskHistoryItemUpdated.
await provider?.postStateToWebviewWithoutTaskHistory()
// Unanswered asks must reach the webview before Message listeners can respond against its state.
const requiresImmediateState =
message.partial === true || (message.type === "ask" && message.isAnswered !== true)
await provider?.postStateToWebviewThrottled()
if (requiresImmediateState) {
await provider?.flushPostStateToWebviewThrottled()
}
this.emit(RooCodeEventName.Message, { action: "created", message })
await this.saveClineMessages()

Expand Down Expand Up @@ -2250,6 +2251,8 @@ export class Task extends EventEmitter<TaskEvents> implements TaskLike {
// Force final token usage update before abort event
this.emitFinalTokenUsageUpdate()

await this.providerRef.deref()?.flushPostStateToWebviewThrottled()

this.emit(RooCodeEventName.TaskAborted)

try {
Expand Down
225 changes: 220 additions & 5 deletions src/core/task/__tests__/Task.spec.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -8,6 +8,7 @@ import { Anthropic } from "@anthropic-ai/sdk"

import {
providerIdentifiers,
RooCodeEventName,
type GlobalState,
type ProviderSettings,
type ModelInfo,
Expand All @@ -27,9 +28,12 @@ import type { ApiMessage } from "../../task-persistence"

type TaskTestAccess = {
getSystemPrompt: () => Promise<string>
getEnabledMcpToolsCount: () => Promise<{ enabledToolCount: number; enabledServerCount: number }>
initiateTaskLoop: (userContent: Anthropic.Messages.ContentBlockParam[]) => Promise<void>
startTask: (task?: string, images?: string[]) => Promise<void>
resumeTaskFromHistory: () => Promise<void>
presentAssistantMessageSafe: () => void
addToClineMessages: (message: import("@roo-code/types").ClineMessage) => Promise<void>
updateClineMessage: (message: import("@roo-code/types").ClineMessage) => Promise<void>
saveClineMessages: () => Promise<boolean>
safeEnsureModelFetched: () => Promise<void>
Expand Down Expand Up @@ -338,6 +342,8 @@ describe("Cline", () => {
mockProvider.postMessageToWebview = vi.fn().mockResolvedValue(undefined)
mockProvider.postStateToWebview = vi.fn().mockResolvedValue(undefined)
mockProvider.postStateToWebviewWithoutTaskHistory = vi.fn().mockResolvedValue(undefined)
mockProvider.postStateToWebviewThrottled = vi.fn().mockResolvedValue(undefined)
mockProvider.flushPostStateToWebviewThrottled = vi.fn().mockResolvedValue(undefined)
mockProvider.getTaskWithId = vi.fn().mockImplementation(async (id) => ({
historyItem: {
id,
Expand Down Expand Up @@ -1029,6 +1035,8 @@ describe("Cline", () => {
say: vi.fn(),
postStateToWebview: vi.fn().mockResolvedValue(undefined),
postStateToWebviewWithoutTaskHistory: vi.fn().mockResolvedValue(undefined),
postStateToWebviewThrottled: vi.fn().mockResolvedValue(undefined),
flushPostStateToWebviewThrottled: vi.fn().mockResolvedValue(undefined),
postMessageToWebview: vi.fn().mockResolvedValue(undefined),
updateTaskHistory: vi.fn().mockResolvedValue(undefined),
}
Expand Down Expand Up @@ -1663,6 +1671,137 @@ describe("Cline", () => {
})
})

describe("webview state throttling", () => {
it("schedules a complete new message without forcing an immediate state push", async () => {
const task = new Task({
provider: mockProvider,
apiConfiguration: mockApiConfig,
task: "test task",
startTask: false,
})
vi.spyOn(getTaskTestAccess(task), "saveClineMessages").mockResolvedValue(true)
const message = {
ts: Date.now(),
type: "say" as const,
say: "text" as const,
text: "message",
}

await getTaskTestAccess(task).addToClineMessages(message)

expect(mockProvider.postStateToWebviewThrottled).toHaveBeenCalledOnce()
expect(mockProvider.postStateToWebviewThrottled).toHaveBeenCalledWith()
expect(mockProvider.flushPostStateToWebviewThrottled).not.toHaveBeenCalled()
expect(mockProvider.postStateToWebviewWithoutTaskHistory).not.toHaveBeenCalled()
})

it("waits for an unanswered ask flush before emitting the message", async () => {
const task = new Task({
provider: mockProvider,
apiConfiguration: mockApiConfig,
task: "test task",
startTask: false,
})
const taskAccess = getTaskTestAccess(task)
vi.spyOn(taskAccess, "saveClineMessages").mockResolvedValue(true)
let releaseFlush!: () => void
const pendingFlush = new Promise<void>((resolve) => {
releaseFlush = resolve
})
const flushSpy = vi.mocked(mockProvider.flushPostStateToWebviewThrottled).mockReturnValueOnce(pendingFlush)
const messageListener = vi.fn()
task.on(RooCodeEventName.Message, messageListener)
const message = {
ts: 1,
type: "ask" as const,
ask: "resume_task" as const,
}

const addPromise = taskAccess.addToClineMessages(message)

await Promise.resolve()
expect(mockProvider.postStateToWebviewThrottled).toHaveBeenCalledOnce()
expect(mockProvider.postStateToWebviewThrottled).toHaveBeenCalledWith()
expect(flushSpy).toHaveBeenCalledOnce()
expect(flushSpy).toHaveBeenCalledWith()
expect(messageListener).not.toHaveBeenCalled()

releaseFlush()
await addPromise

expect(flushSpy.mock.invocationCallOrder[0]).toBeLessThan(messageListener.mock.invocationCallOrder[0])
expect(messageListener).toHaveBeenCalledWith({ action: "created", message })
})
Comment on lines +1698 to +1734

@coderabbitai coderabbitai Bot Jul 31, 2026

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🩺 Stability & Availability | 🟠 Major | ⚡ Quick win

🧩 Analysis chain

🏁 Script executed:

#!/bin/bash
set -euo pipefail

echo "== locate files =="
git ls-files | rg '(^|/)Task\.ts$|(^|/)Task\.spec\.ts$' || true

echo "== Task.spec relevant ranges =="
for f in $(git ls-files | rg 'Task\.spec\.ts$'); do
  echo "--- $f lines 1650-1900"
  sed -n '1650,1900p' "$f" | nl -ba -v1650
done

echo "== Task.ts outline/search around candidate symbols =="
for f in $(git ls-files | rg '^(src/core/task)/Task\.ts$|Task\.ts$'); do
  echo "--- $f"
  wc -l "$f"
  ast-grep outline "$f" --match addToClineMessages --view expanded || true
  ast-grep outline "$f" --match abortTask --view expanded || true
  ast-grep outline "$f" --match messageQueueStateChangedHandler --view expanded || true
  echo "--- postState/flush occurrences"
  rg -n "postStateToWebviewThrottled|flushPostStateToWebviewThrottled|messageQueueStateChangedHandler|TaskAborted|dispose\(" "$f" -C 4
done

Repository: Zoo-Code-Org/Zoo-Code

Length of output: 367

🏁 Script executed:

#!/bin/bash
set -euo pipefail

echo "== Task.spec relevant ranges =="
for f in $(git ls-files | rg 'Task\.spec\.ts$'); do
  echo "--- $f lines 1650-1900"
  sed -n '1650,1900p' "$f" | cat -n
done

echo "== Task.ts candidate occurrences =="
f="src/core/task/Task.ts"
echo "--- $f line count"
wc -l "$f"
echo "--- postState/flush/messageQueue occurrences"
grep -n "postStateToWebviewThrottled\|flushPostStateToWebviewThrottled\|messageQueueStateChangedHandler\|TaskAborted\|dispose(" "$f" -C 8 || true

echo "== addTask/messageQueue abort-like handlers in Task.ts =="
# Use Python to print concise named function blocks if possible without heavy runtime.
python3 - <<'PY'
from pathlib import Path
p=Path('src/core/task/Task.ts')
text=p.read_text()
for needle in ['addToClineMessages', 'messageQueueStateChangedHandler', 'abortTask']:
    print(f'---- {needle} ----')
    i=text.find(needle)
    while i!=-1:
        start=max(0,i-800)
        end=min(len(text),i+2200)
        print(text[start:end])
        print('----')
        i=text.find(needle,end)
PY

Repository: Zoo-Code-Org/Zoo-Code

Length of output: 46233

Add rejection-path coverage for the throttled provider calls.

addToClineMessages awaits postStateToWebviewThrottled() before emitting RooCodeEventName.Message. If flushPostStateToWebviewThrottled() rejects, execution stops before this.emit(RooCodeEventName.Message, ...) and saveClineMessages(). abortTask awaits flushPostStateToWebviewThrottled() before emitting RooCodeEventName.TaskAborted, and disposal only wraps dispose()/saveClineMessages(), so a rejection can prevent post-state flush completion and expose an unwrapped rejection before abort completion.

Add tests in this block, and a rejection-path test near the abort tests, that assert the logged or observable behavior and do not let these rejections propagate.

🤖 Prompt for AI Agents 
Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@src/core/task/__tests__/Task.spec.ts` around lines 1698 - 1734, Add
rejection-path tests for addToClineMessages and abortTask, using rejected
throttled provider calls to verify RooCodeEventName.Message and
RooCodeEventName.TaskAborted behavior remains observable as appropriate. Cover
disposal’s flush path as needed, asserting errors are logged or otherwise
handled and that the rejections do not escape or prevent completion of the
surrounding operation.


it("keeps an already answered ask on the throttled path", async () => {
const task = new Task({
provider: mockProvider,
apiConfiguration: mockApiConfig,
task: "test task",
startTask: false,
})
vi.spyOn(getTaskTestAccess(task), "saveClineMessages").mockResolvedValue(true)

await getTaskTestAccess(task).addToClineMessages({
ts: 1,
type: "ask",
ask: "tool",
isAnswered: true,
})

expect(mockProvider.postStateToWebviewThrottled).toHaveBeenCalledOnce()
expect(mockProvider.postStateToWebviewThrottled).toHaveBeenCalledWith()
expect(mockProvider.flushPostStateToWebviewThrottled).not.toHaveBeenCalled()
})

it("waits for a new partial message flush before a following message update", async () => {
const task = new Task({
provider: mockProvider,
apiConfiguration: mockApiConfig,
task: "test task",
startTask: false,
})
const taskAccess = getTaskTestAccess(task)
vi.spyOn(taskAccess, "saveClineMessages").mockResolvedValue(true)
let releaseFlush!: () => void
const pendingFlush = new Promise<void>((resolve) => {
releaseFlush = resolve
})
const flushSpy = vi.mocked(mockProvider.flushPostStateToWebviewThrottled).mockReturnValueOnce(pendingFlush)
const updatePostSpy = vi.mocked(mockProvider.postMessageToWebview)
const partialMessage = {
ts: 1,
type: "say" as const,
say: "text" as const,
text: "partial message",
partial: true,
}
let partialAddSettled = false
const addThenUpdate = taskAccess.addToClineMessages(partialMessage).then(async () => {
partialAddSettled = true
await taskAccess.updateClineMessage({ ...partialMessage, text: "updated partial" })
})

await Promise.resolve()
expect(mockProvider.postStateToWebviewThrottled).toHaveBeenCalledWith()
expect(flushSpy).toHaveBeenCalledWith()
expect(partialAddSettled).toBe(false)
expect(updatePostSpy).not.toHaveBeenCalled()

releaseFlush()
await addThenUpdate

expect(flushSpy.mock.invocationCallOrder[0]).toBeLessThan(updatePostSpy.mock.invocationCallOrder[0])
expect(updatePostSpy).toHaveBeenCalledWith({
type: "messageUpdated",
clineMessage: {
...partialMessage,
text: "updated partial",
},
})
})
})

describe("abortTask", () => {
it("should set abort flag and emit TaskAborted event", async () => {
const task = new Task({
Expand Down Expand Up @@ -1707,6 +1846,37 @@ describe("Cline", () => {
expect(disposeSpy).toHaveBeenCalled()
})

it("flushes pending state before TaskAborted and disposal while queue state is intact", async () => {
const task = new Task({
provider: mockProvider,
apiConfiguration: mockApiConfig,
task: "test task",
startTask: false,
})
let queuedMessagesAtFlush = -1
const flushSpy = vi.mocked(mockProvider.flushPostStateToWebviewThrottled).mockImplementation(async () => {
queuedMessagesAtFlush = task.messageQueueService.messages.length
})
const emitSpy = vi.spyOn(task, "emit")
const disposeSpy = vi.spyOn(task, "dispose").mockImplementation(() => {})

task.messageQueueService.addMessage("queued text")
await task.abortTask()

const taskAbortedCallIndex = (emitSpy.mock.calls as unknown[][]).findIndex(
([event]) => event === "taskAborted",
)
expect(taskAbortedCallIndex).toBeGreaterThanOrEqual(0)
expect(queuedMessagesAtFlush).toBe(1)
expect(flushSpy).toHaveBeenCalledWith()
expect(flushSpy.mock.invocationCallOrder[0]).toBeLessThan(
emitSpy.mock.invocationCallOrder[taskAbortedCallIndex],
)
expect(emitSpy.mock.invocationCallOrder[taskAbortedCallIndex]).toBeLessThan(
disposeSpy.mock.invocationCallOrder[0],
)
})

it("should work with TaskLike interface", async () => {
const task = new Task({
provider: mockProvider,
Expand Down Expand Up @@ -2741,6 +2911,50 @@ describe("Cline", () => {
})
})

describe("startTask", () => {
it("posts a clean state immediately before adding the first task message", async () => {
const task = new Task({
provider: mockProvider,
apiConfiguration: mockApiConfig,
task: "new task",
startTask: false,
})
const taskAccess = getTaskTestAccess(task)

task.clineMessages = [{ ts: 1, type: "say", say: "text", text: "stale message" }]

let resolvePostState: (() => void) | undefined
const pendingPostState = new Promise<void>((resolve) => {
resolvePostState = resolve
})
const postStateSpy = vi
.mocked(mockProvider.postStateToWebviewWithoutTaskHistory)
.mockImplementationOnce(async () => {
expect(task.clineMessages).toEqual([])
await pendingPostState
})
const saySpy = vi.spyOn(task, "say").mockResolvedValue(undefined)
vi.spyOn(taskAccess, "getEnabledMcpToolsCount").mockResolvedValue({
enabledToolCount: 0,
enabledServerCount: 0,
})
const initiateTaskLoopSpy = vi.spyOn(taskAccess, "initiateTaskLoop").mockResolvedValue(undefined)

const startPromise = taskAccess.startTask("new task")

expect(postStateSpy).toHaveBeenCalledTimes(1)
expect(mockProvider.postStateToWebviewThrottled).not.toHaveBeenCalled()
expect(saySpy).not.toHaveBeenCalled()

resolvePostState?.()
await startPromise

expect(saySpy).toHaveBeenCalledOnce()
expect(saySpy).toHaveBeenCalledWith("text", "new task", undefined)
expect(initiateTaskLoopSpy).toHaveBeenCalledOnce()
})
})

describe("start()", () => {
it("should be a no-op if the task was already started in the constructor", () => {
const task = new Task({
Expand Down Expand Up @@ -2859,9 +3073,9 @@ describe("Cline", () => {
resumeSpy.mockRestore()
})

it("logs (instead of crashing) when postStateToWebviewWithoutTaskHistory rejects from the queue handler", async () => {
it("logs (instead of crashing) when postStateToWebviewThrottled rejects from the queue handler", async () => {
const boom = new Error("postState boom")
mockProvider.postStateToWebviewWithoutTaskHistory = vi.fn().mockRejectedValue(boom)
mockProvider.postStateToWebviewThrottled = vi.fn().mockRejectedValue(boom)

const task = new Task({
provider: mockProvider,
Expand All @@ -2870,13 +3084,14 @@ describe("Cline", () => {
startTask: false,
})

// Triggers messageQueueStateChangedHandler -> void postStateToWebviewWithoutTaskHistory()
// Triggers messageQueueStateChangedHandler -> void postStateToWebviewThrottled()
task.messageQueueService.addMessage("queued text")
await flushMicrotasks()

expect(mockProvider.postStateToWebviewWithoutTaskHistory).toHaveBeenCalled()
expect(mockProvider.postStateToWebviewThrottled).toHaveBeenCalledWith()
expect(mockProvider.postStateToWebviewWithoutTaskHistory).not.toHaveBeenCalled()
expect(consoleErrorSpy).toHaveBeenCalledWith(
"[Task#messageQueueStateChangedHandler] postStateToWebviewWithoutTaskHistory failed:",
"[Task#messageQueueStateChangedHandler] postStateToWebviewThrottled failed:",
boom,
)
})
Expand Down
2 changes: 2 additions & 0 deletions src/core/task/__tests__/Task.throttle.test.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -79,6 +79,8 @@ describe("Task token usage throttling", () => {
log: vi.fn(),
postStateToWebview: vi.fn().mockResolvedValue(undefined),
postStateToWebviewWithoutTaskHistory: vi.fn().mockResolvedValue(undefined),
postStateToWebviewThrottled: vi.fn().mockResolvedValue(undefined),
flushPostStateToWebviewThrottled: vi.fn().mockResolvedValue(undefined),
updateTaskHistory: vi.fn().mockResolvedValue(undefined),
}

Expand Down
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